The present invention relates to thermal transfer recording materials for providing printed images having excellent fastness on diverse receptors.
Conventional thermal transfer recording materials, in general, include those comprising a foundation and, applied onto the foundation, a heat-meltable ink containing a vehicle composed mainly of a wax or another type of heat-meltable ink containing a vehicle composed mainly of a resin for ensuring printed images of good quality even on paper sheets having relatively poor surface smoothness or printed images of high scratch resistance.
Recently, bar code printers and label printers using thermal transfer recording materials have been used to print bar codes or like codes for management of parts or products in production processes of manufacturing factories, merchandise management in the distribution field, management of articles at using sites, and the like. When used in, for example, the distribution field, bar codes are frequently scratched or rubbed. Therefore, such bar codes are required to have particularly high scratch resistance.
As well as for the printing of bar codes, thermal transfer printers have been used in the production of diversified products in small quantities, including outdoor advertising materials, election posters, common posters, standing signboards, stickers, catalogs, pamphlets, calenders and the like in the commercial printing field; bags for light packaging, labels of containers for foods, drinks, medicines, paints and the like, and binding tapes in the packaging field; and labels for indicating quality characteristics, labels for process control, labels for product management and the like in the apparel field. These articles are also required to exhibit scratch resistance.
With respect to the receptors on which bar codes are formed by the thermal transfer method, specialized receptors such as polyethylene terephthalate film subjected to a special surface treatment were used. Recently, plastic films subjected to no surface treatment such as typical polyethylene terephthalate film and vinyl chloride resin film have also been used, which leads to diversification of receptors. More recently, cutting plotters begin to spread and printed films wherein printed images are formed on vinyl chloride resin films by the thermal transfer method are frequently used therefor.
With the conventional thermal transfer recording materials using the heat-meltable ink containing a vehicle composed mainly of a wax, however, resulting printed images exhibit poor scratch resistance though the ink enjoys satisfactory transferability (separability of the ink layer). On the other hand, with the conventional thermal transfer recording materials using the heat-meltable ink containing a vehicle composed mainly of a resin such as ethylene-vinyl acetate copolymer, the transferability of the ink is inferior to the former ink due to its relatively high melt viscosity though resulting printed images enjoy relatively high scratch resistance. Moreover, both of the thermal transfer recording materials provide printed images having poor adhesion to common plastic films, especially vinyl chloride resin films, resulting in poor scratch resistance.
It is, therefore, an object of the present invention to provide a thermal transfer recording material which is capable of exhibiting satisfactory transferability (separability of the ink layer) while at the same time forming printed images having excellent adhesion to diverse plastic films and excellent scratch resistance.
The foregoing and other objects of the present invention will be apparent from the following detailed description.